Does the cod’s
vulnerability allow it to increase its abundance sufficiently at
F=0?

First approach: run all
simulations fitted at V=2, then re-run them with harp seal V=4 unfitted
LoD
Cod
and Capelin biomass versus Harp seal vulnerability change
Note
The present simulations are analogous to those of Vajas et al., but
with three values of v (vulnerability) for ‘harp seal’ (applied to the
harp seal column for all predated species). The figures and tables
present a comparison of the proportion of change between the default
baseline of v=2 and the other v values (implying a more top-down effect
from harp seal on the ecosystem).
Cod simulation : F
scenario V=2 versus V=4

Cod simulation : F
scenario V=2 versus V=10

Caplin simulation :
F scenario V=2 versus V=4

Caplin simulation :
F scenario V=2 versus V=10

Harp seal
simulation : F scenario V=2 versus V=4

Harp seal
simulation : F scenario V=2 versus V=10

Harp seal trends
between V=2, V=4, V=10

Group. Impacted
F Cod
simulation : harp seal vulnerability change
Blank
Changes between V2
and V4
Changes between V2
and V10
F
capelin simulation : harp seal vulnerability change
Blank
Changes between V2
and V4
Changes between V2
and V10
F Harp
seal simulation : harp seal vulnerability change
Blank
Changes between V2
and V4
Changes between V2
and V10
Second approach: run
all simulations fitted at V=2, then re-run them with harp seal V=4
fitted new LoD scale.
In the first approach, we applied changes in V to the exact
simulations proposed in Vajas et al. However, although we ran the
simulations with the same values of F, the correspondence between [F and
LoD for v=2] and [F and LoD for V=4 or 10] is not the same. Here, for
the column of harp seals at V=4 and V=10, we respectively recalculate
the exact LoD values 0%, 10%, 20%, etc. So here we compare a true LoD
10% (v=2) with another true LoD 10% (V=4 and V=10).
New
LoD approximation
Blank
Cod LoD check, harp
seal v = 4

Cod, harp seal v =
10

Capelin, harp seal
v = 4

Capelin, harp seal
v = 10

Harp seal, harp
seal v = 4

Harp seal, harp
seal v = 10

New
LoD simulalations
Note
Here, after finding all the F value for LoD value matches, we run the
final simulations.
Cod, Changes
between V2 and V4

Cod, Changes
between V2 and V10

Capelin, Changes
between V2 and V4

Capelin, Changes
between V2 and V10

Harp seal
reference table
harp seal, Harp
seal V=10
Harp seal, Changes
between V2 and V4

Harp seal, Changes
between V2 and V10

Summary &
comparison vulnerability sensitivity approach
Species changes
Blank
Capelin
## Group_number Group_name
## 1 12 Atlantic cod greater than 35cm
Harp seal
## Group_number Group_name
## 1 11 Greenland shark
## 2 14 Greenland halibut
## 3 22 Other large benthivorous fish
Level of Recovery -
harp seal vulnerability sensitivity
For the new LoR, the approach is slightly different. As the LoR
levels are estimated from a fixed reference value, this will not change
with changes in vulnerability. So for these LoR levels, as in the first
approach, we have simply run the Vajas et al. simulations with different
levels of harp seal vulnerability (harp seal column as predator). The
aim is to check the sensitivity of biomass forcing to changes in
vulnerability.
Vulnerability Sensitivity Analysis
Blank
Cod simulation : B
scenario V=2 versus V=4

Cod simulation : B
scenario V=2 versus V=10

Caplin simulation :
B scenario V=2 versus V=4

Caplin simulation :
B scenario V=2 versus V=10

B Cod
simulation : harp seal vulnerability change
Blank
Changes between V2
and V4
Changes between V2
and V10
B
capelin simulation : harp seal vulnerability change
Blank
Changes between V2
and V4
Changes between V2
and V10
Species change
Blank
Capelin
## Group_number Group_name
## 1 19 American plaice greater than 35cm
## 2 20 American plaice less than 35cm
## 3 27 Sandlance